Isolation of Mucin from Human Submaxillary Secretions

Human submaxillary mucin isolated by precipitation with cetyltrimethylammonium bromide dissolved in 3 M sodium chloride was subjected to gel filtration on Sephadex G-200. This glycoprotein was free of contaminating proteins as determined by gel filtration, disc electrophoresis, and immunologic studies. The molecular weight was between 500,000 and 1,000,000. The amino acid composition was similar to submaxillary mucins from other species; however, the carbohydrate composition of human mucins varied significantly from different individuals. The mucin from secretor, blood group A individuals is completely absorbed by columns of anti-A antibody coupled with Sepharose 4B, indicating that the submaxillary mucin and the blood group substances in saliva are identical.